President Obama can’t help himself. Even as he ordered airstrikes on the Islamic State forces in Iraq threatening to starve, shoot or behead as many as 50,000 refugees trapped on a mountaintop, he had to try to assure the world, his fellow citizens and perhaps, most importantly, himself that the mess wasn’t his fault.

First, he made it clear that he wasn’t the one who wanted to withdraw all U.S. troops from Iraq. It was the Iraqis themselves who insisted we leave, he said, rewriting history as he danced around the question of whether our withdrawal caused or contributed to the collapse of what appeared at the time to be the emergence of a fragile, but potentially stable, Iraq. Whatever happened, he wants us all to know, it wasn’t his fault.

Of course, his promise to end the Iraq war, which he opposed from the beginning, was one of the themes of his 2008 campaign, and it allowed him to vanquish the supposedly unbeatable Hillary Clinton and win in the fall. He reminded us all of that promise when he ordered the last of our combat troops to leave Iraq in 2011: “Today, I can report that, as promised, the rest of our troops in Iraq will come home by the end of the year our troops will definitely be home for the holidays.”

At the time, the president and his supporters viewed his decision to pull all our troops out of Iraq, without leaving the “residual force” of 15,000 to 20,000 military troops on the ground required both to continue to train the Iraqi forces and to provide an atmosphere that would foster political stability, as Mr. Obama delivering on a campaign promise to his political base.

As 2012 approached, the president crowed before audiences large and small of his success in ending the Iraq war. “You know I say what I mean and I mean what I say,” he told an audience in Madison, Wis., and repeated at rally after rally around the country. “I said I’d end the war in Iraq. I ended the war in Iraq.”

That was then, but now jihadists have seized major parts of the country and are burying or beheading men, women and children who won’t convert on the spot to their brand of Islam. As just about everyone is pinning a part of the blame for the current chaos on that decision, the president is claiming that it was a) George Bush’s decision, or b) acquiescence to the desires of the Iraqi government and its people. Neither is true, but will be heard again and again in the coming days.

To set the record straight, the Bush administration always assumed that a residual force would remain in Iraq for some years. While the Obama administration claims the government of Prime Minister Nouri al-Maliki refused to provide the guarantees of legal immunity the United States was seeking, Mr. al-Maliki’s position was that such a guarantee would not pass parliament, but could legally be granted by the prime minister. Our president, who thinks he can do just about everything by executive order, rejected Mr. al-Maliki’s offer and said that if he wouldn’t get parliament to pass it, he (Mr. Obama) would leave Iraq to its own devices, and that’s just what he did.

The decision last week to begin bombing Islamic State forces in Iraq and Monday’s decision to begin arming the Kurds were forced on the president by events. The American people aren’t anxious to go back into Iraq, but the political costs of standing by as jihadists begin their announced genocide against nonbelievers could be unacceptable. The president either had to resort to U.S. airpower and arm the Kurds or be blamed for the imminent death by starvation of as many as 50,000 Yazidi men, women and children trapped in the Sinjar mountains.

He also sent a limited number of U.S. troops back into Iraq to protect our diplomats and other U.S. citizens while perhaps providing a little late training to Iraqi security forces based on Mr. al-Maliki’s renewed promise to grant them the legal immunity Mr. Obama had deemed insufficient earlier. All of these were the right decisions, but the long-suffering Mr. Obama had to make sure we all understood that this is just another mess made by others that he’s being asked to clean up.

If all the blame couldn’t be pinned on Mr. Bush, Mr. Obama had other targets. Our intelligence services failed once again, according to the president, so he had no way of knowing these killers weren’t just al Qaeda’s junior varsity, as he had earlier assumed and besides, the al-Maliki government still hasn’t figured out how to “bring all Iraqis together.”

So what we are witnessing is a president who is doing not what he wants to do, but what he has to and then trying to avoid blame from a base that would just as soon the jihadists have their way with those they hate.

Former Vice President Dick Cheney may not have always gotten it right, but it’s hard to disagree with his observation over the weekend that “they can’t blame George Bush anymore.”